In a security system, a control panel receives signals from security devices distributed throughout a monitoring area, such as a home, business, or warehouse, to monitor various sensor events. The security devices placed throughout the monitoring area might include door/window sensors, glass-break sensors, motion detectors, temperature sensors, smoke sensors, and the like. When a sensor event is sensed, such as a door/window open, movement, smoke, or fire, the sensor sends a sensor event to a control panel, which based on its installation programming and current user setting determines the appropriate system response. In some cases, the control panel will start an entry delay period, in others, e.g. a fire, the control panel may sound an immediate alarm. A system response such as entry delay, can lead to further system actions, such as an alarm and a report of the system condition to an off-premises monitoring station, such as a monitoring company central station, fire station, or police station.
Security systems typically delay reporting some system conditions to the monitoring station for some period of time sufficient to allow a valid user time to disarm the system, that is to change the system state from entry delay to disarmed, prior to the expiration of an entry delay timer and therefore prevent an alarm and consequently an alarm report to the monitoring station. This delay in entering the alarm state is called “entry delay,” as opposed to “dialer delay,” which is an additional time delay between when the control panel enters the alarm state and when the dialer actually reports the alarm via a telephone call to the monitoring station.
Current self-contained security systems—with the user interface, dialer, siren, and processing functions integrated into a single unit—are vulnerable to attack because the entry delay time period gives an unauthorized intruder time to break open and disable the control panel dialer before the control panel has reported the system condition via the dialer. Also, for ease of installation and consumer convenience, the user interface is typically located near the normal premise entry point, which makes it easy for the intruder to find the dialer since they are integrated together. Further, the low-level siren emits sounds during the entry delay period, which are intended to prompt the valid user to disarm the system. But, the siren also aids the intruder in finding the self-contained security system including the critical dialer.
Current hardwired and wireless self-contained security systems typically run a wire from the control panel to the telephone demarcation point (the “head in” point) prior to all telephone sets in the facility. This distance can be quite long, or the ability to install the wire may be very difficult, which makes installation expensive. This wire to the demarcation point is necessary because the security system must be able to seize the telephone line, so that the security system can report a system condition to the monitoring station even if a premise's telephone-set receiver is off-hook. Line seizure means that the control panel disconnects all other premise telephones.
Another disadvantage of current security systems is the expense in isolating the telephone line from alternating current (AC) used by the control panel. Telephone companies, government regulations, and/or safety standards require electrical isolation in order to provide product reliability and ensure customer safety. This is commonly accomplished with an isolation transformer, a transient surge-protection device, and/or other expensive components installed in the control panel, which electrically isolate the AC power from the telephone line and ensure safety.
Thus, a significant need exists for methods and systems that reduce the costs of obtaining security protection and that provide better protection against unauthorized intruders.